Modern telephony networks have been transitioning from the traditional Time Division Multiplexing (TDM) network infrastructures to Internet protocol-based (IP) networks over which voice traffic is carried as packets, which is commonly referred to as voice-over-IP (VoIP). Modern telephony networks also separate media switching and call control functionality. Call control, which includes setting up and tearing down calls and maintaining call state machines, is performed by a network entity referred to as a media gateway controller (MGC). Media stream switching, which includes switching media packets between input and output ports and converting the media packets into the appropriate formats for the sending and receiving parties, is performed by a media gateway (MG). Media gateway controllers communicate call control information to media gateways via a media gateway control protocol, such as media gateway control (MEGACO) and media gateway control protocol (MGCP). Typical media gateway control protocols, such as MGCP and MEGACO, include commands for communicating information about each endpoint of a session to the media gateway and instructing the media gateway as to how to process packets to be delivered to each endpoint.
FIG. 1 is a schematic diagram illustrating first and second media gateways 100 and 102 interconnected through an IP network 104. In FIG. 1 media gateways 100 and 102 communicate via IP network 104. In particular, media gateway 100 connects to IP network 104 via segments 106, 108, and 110 and to next-hop routers 112, 114, and 116. Similarly, media gateway 102 is connected to IP network 104 via next-hop routers 118, 120, and 122 and local route segments 124, 126, and 128.
In the network illustrated in FIG. 1, voice-over-IP sessions may be established between media gateway 100 and media gateway 102. The sessions may be associated with IP paths or routes through IP network 104. If a path or route fails, it may be desirable to reroute the call over another path or route. However, there is currently no known mechanism for performing this action since existing IP routing protocols, such as OSPF, propagate route changes too slowly for calls in progress to be rerouted.
Accordingly, there exists a need for improved methods and systems for detecting a voice-over-IP route failure and for dynamically rerouting calls in response to a route failure.